Pyrenula musaespora Aptroot & M. Cáceres, 2015

Aptroot, André, Andrade, Dannyelly Santos, Mendonça, Cléverton, Lima, Edvaneide Leandro De & Cáceres, Marcela Eugenia Da Silva, 2015, Ten new species of corticolous pyrenocarpous lichens from NE Brazil, Phytotaxa 197 (3), pp. 197-206 : 203-205

Pyrenula musaespora Aptroot & M. Cáceres , sp. nov. ( Fig. 5A–B )

Mycobank #811023

Pyrenula with thallus pale ochraceous, with lichexanthone, ascospores filiform, 3–5-septate, 30–37 × 3–4 μm.

Holotype: — BRAZIL. Sergipe: Santa Luzia do Itanhy, Mata do Crasto ; 11˚22’S, 37˚25’W; alt. c. 10 m; on bark of tree; 26 March 2014, M.E.S. Cáceres & A. Aptroot 18759 ( ISE; isotype: ABL).

showing white ostioles; F, ascospores. A, C & E: bar = 0.5 mm; B & F: bar = 10 μm; D: bar = 5 μm.

Thallus thin, corticate, pale ochraceous, without pseudocyphellae, surrounded by a c. 0.5 mm wide black prothallus line. Ascomata superficial on the bark, conical, 0.4–0.65 mm diam., single, mostly covered by thallus that is revealing the black ascomata in a rather irregular area around the ostiole. Wall carbonized all around. Ostiole apical, black. Hamathecium inspersed with hyaline oil droplets. Ascospores 8/ascus, brown, in one bundle (all mostly overlapping), filiform, 3–5-septate, 30–37 × 3–4 μm, lumina long elongated, separated from the wall by a relatively thick layer of endospore, ends pointed. Pycnidia not observed. Chemistry: Thallus UV + yellow; TLC: lichexanthone.

Ecology and distribution: —On smooth bark in undisturbed Atlantic rain forest. Only known from Brazil.

Discussion: —Filiform ascospores are rare in the genus Pyrenula , and there is only one species known with filiform ascospores that are also 3–5-septate, viz. P. melanophthalma (Mont.) Trevis. ( Trevisan 1853: 17). This species differs because the hamathecium is not inspersed and the thallus contains no anthraquinone. The new species has the characteristic ochraceous thallus colour of crustose lichens that contain much lichexanthone in the cortex; it could therefore already be recognized in the field as a probably undescribed species.

Additional specimen examined: — BRAZIL. Sergipe: Santa Luzia do Itanhy, Mata do Crasto ; 11˚22’S, 37˚25’W; alt. c. 10 m; on bark of tree; 26 March 2014, M.E.S. Cáceres & A. Aptroot 18808 ( ISE; ABL, topotypes) .

Figures

FIGURE 5. Pyrenula musaespora (isotype ABL); A, habitus showing black ascomata emerging from ochraceous thallus; B, ascospore; C–D, P. rubrolateralis (isotype ABL); C, habitus showing a red ostiole; D, ascospores; E–F, Thelenella lateralis (isotype ABL); E, habitus